Apparatus for proportioning liquids



1951 H. G. FREEMAN 2,580,011

APPARATUS FOR PROPORTIONING LIQUIDS Filed Oct. 6, 1948 I INVEN TOR.

Patented Dec. 25, 1951 APPARATUS FOR L b l v of Massachusetts Application October 6, 1948, Serial No. 52,992

2 Claims.

The present invention relates to methods and apparatus for proportioning liquids and more particularly to systems for proportioning foam liquid in fire fighting systems.

The present invention is particularly adaptable in fixed installations, such as gasoline tank farms, where foam connections are made to the various tanks. It is desirable to use a single source of water and a single source of foam liquid. The various lines are brought into operation by automatic means depending on the presence of a fire. It is important to maintain a substantially uniform mixture of foam and water regardless of the number of branch lines that are brought into operation.

According to the present invention there is provided a single water supply under pressure, a single foam supply under somewhat higher pressure, and individual connections from the water supply and the foam supply to branch lines leading to the various points at which the foam is to be discharged. Suitable check valves are provided whereby the foam liquid can be discharged only into such branch lines as are open for the discharge of liquid.

In the accompanying drawings Fig. 1 is a diagram of the preferred system according to the,

present invention, Fig. 2 is a detail view on an enlarged scale.

In Fig. 1 there is shown a foam system including a main water supp y line 2 connected with branch lines 4, 6, 8, l0, l2 and I4 leading to nozzles I 6 preferably arranged in proximity to the tanks to be protected. A foam tank 20 is connected through a foam pump 22 with a line 24 having branch l nes 26, 28, etc. leading into the lines 4, 6, 8, l0, I2 and i 4 respectively. Each of the branch lines has a control valve. The control valve for the branch line 4 is indicated at 30. This control valve 38 is preferably operated automatically, as by temperature or pressure-responsive means at the hazard area. The individual foam lines 26, 28, etc., connect directly into the branch lines in back of the control valve 30 as clearly indicated in the diagram. A check valve 32 is provided in each branch line immediately beyond the point of connection to the water supply line 2. Thus it will be noted that the inlet for the foam into each branch line is between the check valve 32 and the control valve 30. When the control valve in any line is closed, the foam is not permitted to discharge into the line.

The water supply is under substantially constant pressure and the foam pump 22 is preferably a constant pressure pump. The pump 22 may be operated continuously but preferably is maintained under automatic control whereby it is caused to start up whenever a fire is detected at any place in the hazard area.

In the event of a fire, one or more of the control valves 30 are opened, depending upon the extent and severity of the fire. At the same time the pump 22 is started if it is not maintained continuously in operation. Eachfoam line 26 is provided with a throttling plate 34 having a suitable orifice to reduce the foam liquid pressure whenever any substantial capacity of foam liquid is forced through the line 26.

If only one of the branch lines is open at the time of the fire, only a suflicient amount of foam liquid will flow through the line 26 into the pipe 4 to give the proper proportions of foam with water for that line. Although the foam liquid is under somewhat higher pressure than the water, the foam is prevented from getting into the main water supply line by reason of the check valves. Under -flow conditions when the check valve is open, the flow of water is so great y increased over the flow of foam that foam liquid is carried with the water to the nozzle.

As more branch lines are open by reason of the existence of a fire of sufficient spread, the proper amount of foam liquid is discharged into each of them in order that the proper mixture of water and foam li uid is automatically mainta ned for each of the lines.

Havin thus described the invention, I claim:

1. A liquid proportioning system for a foam system comprising a main water supply line, under substantially constant water pressure, branch lines from the main line, each branch line having a check valve and a control valve on the dischar e side of the check va ve, a foam liquid supply, a foam pump for applying to the foam liquid a pressure substantially in excess of the water pressure, foam lines for conveying foam liquid under pressure from the foam pump to the individual branch lines, each foam line being connected to its branch line between the check valve and the control valve, and throttling means having a fixed orifice in each foam line.

2. A liquid proportioning system for a foam sytem comprising a main water supply line under substantially constant water pressure, branch lines from the main line, a check valve in each branch line, a control valve in each branch line on the discharge side of the check valve, a foam liquid supply, a foam pump-for applying to the foam liquid a constant pressure substantially in v. 3 4 excess of the water pressure, foam lines for con- REFERENCES CITED veying foam liquid under pressure from the foam The f no pmnp to the individual branch lines, each foam file of g gggff are of record m the line being connected to its branch line between the check valve and the control valve, and throt- 5 UNITED STATES PATENTS tle plates in each branch line having fixed ori- Number Name Date fices constructed with respect to the pressure difference between theliquids in the-branch line iggggggg 29 5:? 1 133 and the Ioam' line and the volume of flow in 1c er 9 a 2 4 the branch line when the control valve is open 10 to permit passage of a predetermined proportion of foam into the branch line when the said control valve is open.

HOWARDGJ'REEMAN. 

